Re: tagger field map

[Alexander Somov <somov@jlab.org>]

Good morning,

Yang thanks for the information.

The question is should we shift the magnets or the
electron beam pipe which goes to the dump (downstream
by 19.6 cm)?

Should we shift the quadrupole magnet as well (or one can
simply change the quadrupole's field) ?

Cheers,
        Sascha








On Mon, 12 Jan 2009, Tim Whitlatch wrote:

> Good morning all,
>
> We do not wish to change the Tagger hall. Is there an exact number that we 
> should shift the magnet by? Or is 20cm fine?
>
> Thanks,
>
>      Tim
>
> Guangliang Yang wrote:
>> Dear Sascha,
>>
>>    The number in table 4.2 was calculated for the two dipole tagger. It is 
>> not correct for the single magnet tagger.  If we don't want to change the 
>> tagger hall design, we should shift the tagger downstream by ~20 cm.
>> 
>> 
>> Cheers
>> 
>> Yang
>> 
>> 
>> 
>> ----- Original Message ----- From: "Alexander Somov" <somov@jlab.org>
>> To: "Richard Jones" <richard.t.jones@uconn.edu>
>> Cc: <halld-tagger@jlab.org>
>> Sent: Friday, January 09, 2009 3:53 PM
>> Subject: tagger field map
>> 
>> 
>>> 
>>> Hello Richard,
>>> 
>>> The magnetic field map in the tagger hall seems
>>> to be shifted by a few cm in the MC.
>>> 
>>> According to the table 4.2 in the technical design
>>> report (updated for the review), the position of
>>> 12 GeV electrons at z=26.301 m should be x = -4.7576 m.
>>> However, I get x = -4.803 m, see the plot attached.
>>> Are the numbers in the table 4.2 correct ?
>>> 
>>> I used the same reconstruction code as before but just
>>> replaced the magnetic field map (do I need to shift the
>>> map ?)
>>> 
>>> Could you please check. I want to finish with updating
>>> geometry asap.
>>> 
>>> Thanks,
>>>        Sascha
>>> 
>>> P.S. The full-energy deflection angle in the magnet is
>>> correct, 13.4 deg.
>>> 
>>> 
>> 
>